Soil stratigraphy in a deeply weathered shield landscape in south-western Australia

Abstract

Soil stratigraphy on an erosionally modified deeply weathered shield landscape in south-western Australia is described. in situ development of deep profiles of weathering are indicated by preservation of weathered rock fabrics and intact quartz veins. The independence of sedimentary layers is shown by reference to lateral trends within layers, by the relationship of these trends to associated layers, and by certain distribution patterns of mineral grains and reverse weathering patterns between layers. The succession of soil-stratigraphic layers described is used as a basis to interpret profile morphology and aspects of landform development. Striking features of soil morphology and soil pattern can be related to soil stratigraphy and hence to landform history rather than to pedogenic processes. In particular, texture contrast profiles relate to superposition of a shallow slope sediment on clayey saprolite. Red and yellow earths relate to deep phases of this sediment or to erosional exposure of elements of the profiles of deep weathering.